From f01ff850ab9bb09b6d61f7990840b6f3319a6e9c Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Wed, 26 Oct 2022 14:57:09 +0200
Subject: [PATCH] Add mutex, rename variables, update logging

---
 appservice/appservice.go  |  7 +++++--
 appservice/query/query.go | 32 +++++++++++++++++++-------------
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/appservice/appservice.go b/appservice/appservice.go
index 9000adb1d..0c778b6ca 100644
--- a/appservice/appservice.go
+++ b/appservice/appservice.go
@@ -18,6 +18,7 @@ import (
 	"context"
 	"crypto/tls"
 	"net/http"
+	"sync"
 	"time"
 
 	"github.com/gorilla/mux"
@@ -58,8 +59,10 @@ func NewInternalAPI(
 	// Create appserivce query API with an HTTP client that will be used for all
 	// outbound and inbound requests (inbound only for the internal API)
 	appserviceQueryAPI := &query.AppServiceQueryAPI{
-		HTTPClient: client,
-		Cfg:        &base.Cfg.AppServiceAPI,
+		HTTPClient:    client,
+		Cfg:           &base.Cfg.AppServiceAPI,
+		ProtocolCache: map[string]appserviceAPI.ASProtocolResponse{},
+		CacheMu:       sync.Mutex{},
 	}
 
 	if len(base.Cfg.Derived.ApplicationServices) == 0 {
diff --git a/appservice/query/query.go b/appservice/query/query.go
index 126cf0e7a..83e31b755 100644
--- a/appservice/query/query.go
+++ b/appservice/query/query.go
@@ -23,6 +23,7 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
 
 	"github.com/opentracing/opentracing-go"
 	"github.com/sirupsen/logrus"
@@ -39,7 +40,8 @@ const userIDExistsPath = "/users/"
 type AppServiceQueryAPI struct {
 	HTTPClient    *http.Client
 	Cfg           *config.AppServiceAPI
-	protocolCache map[string]api.ASProtocolResponse
+	ProtocolCache map[string]api.ASProtocolResponse
+	CacheMu       sync.Mutex
 }
 
 // RoomAliasExists performs a request to '/room/{roomAlias}' on all known
@@ -208,7 +210,7 @@ func (a *AppServiceQueryAPI) Locations(
 	}
 
 	for _, as := range a.Cfg.Derived.ApplicationServices {
-		var proto []api.ASLocationResponse
+		var asLocations []api.ASLocationResponse
 		params.Set("access_token", as.HSToken)
 
 		url := as.URL + api.ASLocationPath
@@ -216,12 +218,12 @@ func (a *AppServiceQueryAPI) Locations(
 			url += "/" + req.Protocol
 		}
 
-		if err := requestDo[[]api.ASLocationResponse](a.HTTPClient, url+"?"+params.Encode(), &proto); err != nil {
-			log.WithError(err).Error("unable to get protocolResponse from application service")
+		if err := requestDo[[]api.ASLocationResponse](a.HTTPClient, url+"?"+params.Encode(), &asLocations); err != nil {
+			log.WithError(err).Error("unable to get 'locations' from application service")
 			continue
 		}
 
-		resp.Locations = append(resp.Locations, proto...)
+		resp.Locations = append(resp.Locations, asLocations...)
 	}
 
 	if len(resp.Locations) == 0 {
@@ -243,7 +245,7 @@ func (a *AppServiceQueryAPI) User(
 	}
 
 	for _, as := range a.Cfg.Derived.ApplicationServices {
-		var proto []api.ASUserResponse
+		var asUsers []api.ASUserResponse
 		params.Set("access_token", as.HSToken)
 
 		url := as.URL + api.ASUserPath
@@ -251,12 +253,12 @@ func (a *AppServiceQueryAPI) User(
 			url += "/" + req.Protocol
 		}
 
-		if err := requestDo[[]api.ASUserResponse](a.HTTPClient, url+"?"+params.Encode(), &proto); err != nil {
-			log.WithError(err).Error("unable to get protocolResponse from application service")
+		if err := requestDo[[]api.ASUserResponse](a.HTTPClient, url+"?"+params.Encode(), &asUsers); err != nil {
+			log.WithError(err).Error("unable to get 'user' from application service")
 			continue
 		}
 
-		resp.Users = append(resp.Users, proto...)
+		resp.Users = append(resp.Users, asUsers...)
 	}
 
 	if len(resp.Users) == 0 {
@@ -276,7 +278,9 @@ func (a *AppServiceQueryAPI) Protocols(
 	// get a single protocol response
 	if req.Protocol != "" {
 
-		if proto, ok := a.protocolCache[req.Protocol]; ok {
+		a.CacheMu.Lock()
+		defer a.CacheMu.Unlock()
+		if proto, ok := a.ProtocolCache[req.Protocol]; ok {
 			resp.Exists = true
 			resp.Protocols = map[string]api.ASProtocolResponse{
 				req.Protocol: proto,
@@ -285,11 +289,10 @@ func (a *AppServiceQueryAPI) Protocols(
 		}
 
 		response := api.ASProtocolResponse{}
-		log.Debugf("XXX: getting single protocol")
 		for _, as := range a.Cfg.Derived.ApplicationServices {
 			var proto api.ASProtocolResponse
 			if err := requestDo[api.ASProtocolResponse](a.HTTPClient, as.URL+api.ASProtocolPath+req.Protocol, &proto); err != nil {
-				logrus.WithError(err).Error("unable to get protocolResponse from application service")
+				logrus.WithError(err).Error("unable to get 'protocol' from application service")
 				continue
 			}
 
@@ -337,7 +340,10 @@ func (a *AppServiceQueryAPI) Protocols(
 		return nil
 	}
 
-	a.protocolCache = response
+	a.CacheMu.Lock()
+	defer a.CacheMu.Unlock()
+	a.ProtocolCache = response
+
 	resp.Exists = true
 	resp.Protocols = response
 	return nil